Water recovery

Factors affecting RO membrane separations and water flux include feed variables such as solute concentration, temperature, pH, and pretreatment requirements membrane variables such as polymer type, module geometry, and module arrangement and process variables such as feed flow rate, operating time and pressure, and water recovery. 

Tar sand, also variously called oil sand (in Canada) or bituminous sand, is the term commonly used to describe a sandstone reservoir that is impregnated with a heavy, viscous black extra heavy cmde oil, referred to as bitumen (or, incorrectly, as native asphalt). Tar sand is a mixture of sand, water, and bitumen, but many of the tar sand deposits in the United States lack the water layer that is beHeved to cover the Athabasca sand in Alberta, Canada, thereby faciHtating the hot-water recovery process from the latter deposit. The heavy asphaltic organic material has a high viscosity under reservoir conditions and caimot be retrieved through a weU by conventional production techniques. 

Bromley and co-workers (36) have calculated the minimal energy of separation of water from seawater containing 3.45 wt % salt, at 25°C, to be 2.55 kj/(kg fresh water) for the case of 2ero fresh water recovery (infinitesimal concentration change) and 2.91 kj/(kg fresh water) for the case of 25% fresh water recovery. is, however, severalfold smaller than the energy necessary for water desalination ia practice. 

In a permeation experiment, an HERO module with a membrane area of 200 m is used to remove a nickel salt from an electroplating wastewater. TTie feed to the module has a flowrate of 5 x IQ— m /s, a nickel-salt composition of 4,(X)0 ppm and an osmotic pressure of 2.5 atm. The average pressure difference across the membrane is 28 atm. The permeate is collected at atmospheric pressure. The results of the experiment indicate that the water recovery is 80% while the solute rejection is 95%. Evaluate the transport parameters Ay and (D2u/KS). 

Water recovery (or conversion) is the ratio of the permeate flowrate to the feed flowrate x 100% Solute rejection is defined as (1 - Cp/Cf ) x 100%. 

In Example 11.1, the water recovery (permeate flowrate/feed flowrate) was 0.41. It is desired to increase water recovery by designing a multistage system. Two additional RO stages are to be used to process the reject from the first stage. Figure 11.7 illustrates... 

Heat rejection is only one aspect of thermal management. Thermal integration is vital for optimizing fuel cell system efficiency, cost, volume and weight. Other critical tasks, depending on the fuel cell, are water recovery (from fuel cell stack to fuel processor) and freeze-thaw management. 

Therefore, the single-pump method is commonly used only for smaller spills when the gasoline-water recovery rates are relatively low (e.g., less than 1892 L/h or 500 gal/h). 

This system consists of an in situ polyethylene tank, an application system, and a bottom water recovery system.65 An underlying, permeable, water-bearing zone facilitates the creation of ingradient water flow conditions. The tank defines the treatment area, minimizes the potential for release of bacterial cultures to the aquifer, and maintains contaminant concentration levels that facilitate treatment. The ingradient conditions facilitate reverse leaching or soil washing and minimize the potential for outmigration of contaminants. 

The bottom water recovery system uses existing wells or new wells to create the water recovery system for removal of the water used to wash the contaminated soil. Reverse leaching or soil washing can be conducted by controlling the water levels within the tank. This design minimizes the volume of clean ex situ water entering the system for treatment. Extremely dense clays may be difficult to treat with this technology. 

MPE provides several advantages when compared with the use of SVE or pump-and-treat alone. MPE provides for an increase in groundwater recovery rates, an increase in ROI in individual ground-water recovery wells, and recovery of shallow free product. By depressing the groundwater table in the vicinity of the extraction wells, MPE provides for remediation of the capillary fringe and smear zone, and remediation of volatile, residual contaminants located above and below the water table.46... 

Vourch et al49 studied the applicability of the RO process for the dairy industry wastewater. The treated wastewater total organic carbon (TOC) was <7 mg/L. It was found that in order to treat a flow of 100 m3/d, 540 m2 of the RO unit is required with 95% water recovery. Dead-end NF and RO were studied for the treatment of dairy wastewater.50 Permeate COD, monovalent ion rejection, and multivalent ion rejection for the dead-end NF were reported as 173-1095 mg/L, 50-84%, and 92.4-99.9%, respectively. When it comes to the dead-end RO membranes, the values for permeate COD, monovalent ion removal, and multivalent ion removal were 45-120 mg/L, >93.8%, and 99.6%, respectively. Membrane filtration technology can be better utilized as a tertiary treatment technology and the resultant effluent quality will be high. There can be situations where the treated effluents can be reused (especially if RO is used for the treatment). 

Leitner, G.F. Reverse Osmosis for Water Recovery and Reuse, Chemical Engineering Progress, June 1973, p. 83. 

Clearly, one option to reduce the add-on is to use high-efficiency size formulations. However, there is a limit to what can be achieved by this approach. Even if the add-on is reduced to only 5%, the pollution load is still substantial. The two main options to facilitate disposal are (a) recovery of size polymers and (b) biological effluent treatment. Recovery of size polymers, particularly from water-soluble synthetic sizes, is based on extraction washing using the minimum quantity of water. Recovery rates in the region of 50% have been quoted for polyfvinyl alcohol) and carboxymethylcellulose size formulations. It is necessary to apply one of three concentration techniques precipitation, condensation or ultrafiltration [205]. 

Recoflo An ion-exchange process based on short beds and small beads. Developed by the University of Toronto in the 1960s and commercialized by Eco-Tec, Canada. Used for waste-water recovery and removal of metals from various metallurgical waste streams. In 1988,500 units had been installed in 27 countries. 

Recovery — Recovery control (RC) solutions were prepared in 10/90 v/v ACN/water. Recovery evaluation (RE) samples were prepared in human plasma. Aliquot of RC solutions into assay plates followed sample preparation procedure steps 1 and 2. Instead of adding 50 pL of diluent, wells containing RC solutions were dried down under a steady stream of room temperature N2. The dried wells were then reconstituted with 250 pL of diluent. Reconstituted RC solutions were directly injected onto an HPLC analytical column, bypassing the extraction column. RE samples were aliquoted into an assay plate following normal sample preparation. RE samples were analyzed using the full extraction procedure (with extraction column). The analyte was tested at three concentration levels and the internal standard was tested at one. Mean extraction recovery for fenofibric acid varied from 93.2 to 111.1%, and mean extraction recovery for the Pestanal internal standard was 105.2%. 

Kappen, J. and Wilderer, P.A., Key parameter methodology for increased water recovery in the pulp and paper industry, Chapter 12 in Water recycling and resource recovery in... 

This area of recombinant DNA technology also has application in the degradation of solid waste materials In waste water recovery, in leaching minerals from ore-containing rock, in improved oil recovery, and in the decontamination of chemical waste dumps through the engineering of microorganisms that can destroy specific toxic contaminants. 

Lack of a theoretical response or inflection point due to an inordinate length of time for water recovery ... 

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